Lids and containers molded on resilient plastic material, such as polyethylene and polypropylene, are convenient, economical, and effective. The lid and container combination may be made reusable whereby the lid may be replaced and removed again and again after the first opening. Although reusability is a convenience for the user, there is a risk that tamperers, thieves or mishaps may lift the lid, contaminate or remove some of the contents, and replace the lid without leaving visible evidence of removal, unless provision is made to indicate otherwise. In the case of containers for foods and some other products, such provision in tamper-indicating container and lid combinations has become necessary or highly desirable in order to protect the consumer.
Various kinds of tamper-indicating containers are in current use. One type has a thin, transparent membrane closing the mouth of the container, and frequently is further provided with a lid which covers the membrane and is secured to the rim of the container. Another type includes a seal bridging adjacent portions of the lid and the container and which is secured to such respective adjacent portions. Still another type has a tear strip interconnected to the lid and extending about the sidewall of the container below an annular bulge in the container, whereby the lid cannot be removed without breaking the interconnection between the tear strip and the lid.
As indication of tampering is provided by the present invention without requiring a membrane at the mouth of the container, without the need for a seal bridging the lid and the container, and without a tear strip interconnected to the lid. Yet, the convenience of reusability is retained together with the effectiveness and economy afforded by molding the separate lids and containers of resilient plastic material.